From eb6f803941c809bf7e6e22f7f43295c6d5977c1e Mon Sep 17 00:00:00 2001
From: Koichi ITO <koic.ito@gmail.com>
Date: Fri, 20 Aug 2021 02:02:20 +0900
Subject: [PATCH] + ruby31.y: Allow omission of parentheses in one line pattern
 matching

Closes #815.

This commit tracks upstream commit https://github.com/ruby/ruby/commit/ecb6d6a
---
 lib/parser/ruby31.y |  4 +--
 test/test_parser.rb | 66 +++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 66 insertions(+), 4 deletions(-)

diff --git a/lib/parser/ruby31.y b/lib/parser/ruby31.y
index 73a28428f..9b0062c28 100644
--- a/lib/parser/ruby31.y
+++ b/lib/parser/ruby31.y
@@ -371,7 +371,7 @@ rule
                       result = @lexer.in_kwarg
                       @lexer.in_kwarg = true
                     }
-                  p_expr
+                  p_top_expr_body
                     {
                       @pattern_variables.pop
                       @lexer.in_kwarg = val[2]
@@ -386,7 +386,7 @@ rule
                       result = @lexer.in_kwarg
                       @lexer.in_kwarg = true
                     }
-                  p_expr
+                  p_top_expr_body
                     {
                       @pattern_variables.pop
                       @lexer.in_kwarg = val[2]
diff --git a/test/test_parser.rb b/test/test_parser.rb
index ac851e0bc..7aa78c7a1 100644
--- a/test/test_parser.rb
+++ b/test/test_parser.rb
@@ -9614,6 +9614,68 @@ def test_pattern_matching_single_line
       SINCE_3_0)
   end
 
+  def test_pattern_matching_single_line_allowed_omission_of_parentheses
+    assert_parses(
+      s(:begin,
+        s(:match_pattern,
+          s(:array,
+            s(:int, 1),
+            s(:int, 2)),
+          s(:array_pattern,
+            s(:match_var, :a),
+            s(:match_var, :b))),
+        s(:lvar, :a)),
+      %q{[1, 2] => a, b; a},
+      %q{~~~~~~~~~~~~~~ expression (match_pattern)
+        |       ~~ operator (match_pattern)},
+      SINCE_3_1)
+
+    assert_parses(
+      s(:begin,
+        s(:match_pattern,
+          s(:hash,
+            s(:pair,
+              s(:sym, :a),
+              s(:int, 1))),
+          s(:hash_pattern,
+            s(:match_var, :a))),
+        s(:lvar, :a)),
+      %q{{a: 1} => a:; a},
+      %q{~~~~~~~~~~~~ expression (match_pattern)
+        |       ~~ operator (match_pattern)},
+      SINCE_3_1)
+
+    assert_parses(
+      s(:begin,
+        s(:match_pattern_p,
+          s(:array,
+            s(:int, 1),
+            s(:int, 2)),
+          s(:array_pattern,
+            s(:match_var, :a),
+            s(:match_var, :b))),
+        s(:lvar, :a)),
+      %q{[1, 2] in a, b; a},
+      %q{~~~~~~~~~~~~~~ expression (match_pattern_p)
+        |       ~~ operator (match_pattern_p)},
+      SINCE_3_1)
+
+    assert_parses(
+      s(:begin,
+        s(:match_pattern_p,
+          s(:hash,
+            s(:pair,
+              s(:sym, :a),
+              s(:int, 1))),
+          s(:hash_pattern,
+            s(:match_var, :a))),
+        s(:lvar, :a)),
+      %q{{a: 1} in a:; a},
+      %q{~~~~~~~~~~~~ expression (match_pattern_p)
+        |       ~~ operator (match_pattern_p)},
+      SINCE_3_1)
+  end
+
   def test_ruby_bug_pattern_matching_restore_in_kwarg_flag
     refute_diagnoses(
       "p(({} in {a:}), a:\n 1)",
@@ -9703,7 +9765,7 @@ def test_pattern_matching_required_parentheses_for_in_match
       [:error, :unexpected_token, { :token => 'tCOMMA' }],
       %{1 => a, b},
       %{      ^ location},
-      SINCE_3_0)
+      %w(3.0))
 
     assert_diagnoses(
       [:error, :unexpected_token, { :token => 'tASSOC' }],
@@ -9715,7 +9777,7 @@ def test_pattern_matching_required_parentheses_for_in_match
       [:error, :unexpected_token, { :token => 'tLABEL' }],
       %{1 => a:},
       %{     ^^ location},
-      SINCE_3_0)
+      %w(3.0))
   end
 
   def test_pattern_matching_required_bound_variable_before_pin